private void InjectTailCall()
{
for (var i = 0; i < IL.Index; i++)
{
var instr = IL[i];
BufferedILInstruction call = null;
if (instr.IsInstruction == OpCodes.Ret)
{
int callIx = -1;
for (var j = i - 1; j >= 0; j--)
{
var atJ = IL[j];
if (atJ.MarksLabel != null)
{
break;
}
if (atJ.IsInstruction.HasValue)
{
if (ExtensionMethods.IsTailableCall(atJ.IsInstruction.Value))
{
callIx = j;
call = atJ;
}
break;
}
}
if (callIx == -1)
{
continue;
}
if (call.TakesManagedPointer())
{
continue;
}
#if !COREFX // see https://github.com/dotnet/corefx/issues/4543 item 4
if (call.TakesTypedReference())
{
continue;
}
#endif
if (call.TakesByRefArgs())
{
continue;
}
InsertInstruction(callIx, OpCodes.Tailcall);
i++;
}
}
}
private void InjectTailCall()
{
for (var i = 0; i < IL.Index; i++)
{
var instr = IL[i];
BufferedILInstruction call = null;
if (instr.IsInstruction == OpCodes.Ret)
{
int callIx = -1;
for (var j = i - 1; j >= 0; j--)
{
var atJ = IL[j];
if (atJ.MarksLabel != null)
{
break;
}
if (atJ.IsInstruction.HasValue)
{
if (ExtensionMethods.IsTailableCall(atJ.IsInstruction.Value))
{
callIx = j;
call = atJ;
}
break;
}
}
if (callIx == -1)
{
continue;
}
if (call.TakesManagedPointer())
{
continue;
}
// TODO: see https://github.com/dotnet/corefx/issues/4543 item 4
#if !NETSTANDARD
if (call.TakesTypedReference())
{
continue;
}
#endif
if (call.TakesByRefArgs())
{
continue;
}
var callReturns = call.MethodReturnType;
var delegateReturns = ReturnType.Type;
// the method's return types not matching
// means we can't just turn the call into a jump
// since _something_ has to preceed or survive the call to
// make the ret legal
if (!ExtensionMethods.IsAssignableFrom(delegateReturns, callReturns))
{
continue;
}
// there's one case not being handled explicitly here,
// which is the call must consume the _entire_ stack.
// we don't have to asset it because the return type
// comparison is sufficient:
// - if the types match, the stack must be empty
// or the following ret will fail to verify (since
// there's an extra item of the corret type on the stack)
// - if the types _don't_ match, we've already bailed on the
// tail injection
InsertInstruction(callIx, OpCodes.Tailcall);
i++;
}
}
}